Principles of Inheritance and Variation — BIOLOGY STD 12 Science — Question

1. Explain the phenomenon of multiple allelism and co-dominance taking ABO blood group as an example,
2. What is the phenotype of the following:

1. I^Ai
2. ii

1. State one difference and one similarity between geitonogamy and xenogamy.
2. Explain any three devices developed in flowering plants to discourage self pollination and encourage cross-pollination.

1. Draw a pyramid of numbers of a situation, where a large population of insects feeds upon a very big tree. The insects in turn are eaten by small birds, which in turn are fed upon by big birds.
2. Differentiate, giving reason, between the pyramid of biomass of the above situation and the pyramid of numbers that you have drawn.

OR

In a botanical garden of a city there is a huge banyan tree growing on which hundreds of birds and thousands of insects live. Draw the pyramids of numbers and also biomass represented by this community. Comment giving reasons on the two different pyramids drawn.

1. What is drug abuse?
2. Name some commonly abused drugs and their source.
3. What should be the attitude of his parents after his return?
4. What values did the principal reflect through his initiative?